This is a common discussion on the forum.
Check out the search results for “fire safe” and you will have a lot of reading to do: link
TLDR: What you’ve linked is a reasonable option but do note that in a total loss house fire the safe is likely to have internal temperatures exceeding the limits that PSA slabs can handle. @silversnorlax204 did work on the max temps of PSA slabs and they are lower than paper documents, USB media and things like that require. linkI personally use a small chest or file safe nested inside of a larger gun fire safe to have exponential further protection fire wise. Silver snorlax also did some good work on that. link